What is the GCF of 105 and 90?
GCF of two numbers 105 and 90 is the largest number which divides both the numbers exactly.
Answer: GCF of 105 and 90 is 15
Let's find the GCF of 105 and 90.
Explanation
The GCF of 105 and 90 is the largest number which divides both the numbers completely with no remainder.
We will use the following two methods to find the GCF of 105 and 90.
 GCF of 105 and 90 by Division Method
 GCF of 105 and 90 by Listing Method
Method 1: GCF of 105 and 90 by Long Division

Step 1: Divide the greater number 150 by the smaller number 80 and the remainder left is 15.

Step 2: Take the remainder 15 as the divisor and 90 as the dividend and perform the long division again.

Step 3: Continue till you get the remainder as 0 and the last divisor 15 is the GCF of 105 and 90.
Method 2: GCF of 105 and 90 by Listing the Common Factors
In this method, we will find the common factors of 105 and 90.
Factors of 90 are 1, 2, 3, 5, 6, 9, 10, 15, 18, 30, 45, and 90
Factors of 105 are 1, 3, 5, 7, 15, 21, 35, 105
The common factor of 90 and 105 are 1, 3, 5, and 15.
The greatest common factor of 90 and 105 is 15